To provide a heating and cooling system using underground heat constituted to have an underground heat space on an outer wall side of an underground building to enable heat exchange.

In the heating and cooling system using underground heat, first steel materials 3 are mounted on the outer wall of the underground building 2 positioned in the lower part of a ground building 1, and iron plates 15 are provided astride the first steel materials 3 on ground wall sides of the first steel materials for earth retention. A space of the first steel material 3 between inner wall members 6, 7, 8 provided inside the first steel material 3 and the iron plate 15 is used as the underground heat space 10 for retaining air with underground heat. Second steel materials 4 jointed to the iron plates 15 are embedded around the underground building 2. The air including underground heat absorbed by the steel materials is circulated in a space with the ground building 1 via the underground heat space 10, so as to perform heating and cooling.